1. Technical Field
The present invention relates to a handpiece for treating anatomy utilizing ultrasonic vibration generated by an ultrasonic transducer and an ultrasonic treatment apparatus provided with the handpiece, and in particular, to the handpiece with a structure preventing transmission of heat and vibration caused when the ultrasonic transducer is driven to continuously generate ultrasound vibration and the ultrasonic treatment apparatus provided with the handpiece with the heat/vibration blocking structure.
2. Related Art
Ultrasonic treatment apparatuses have been known as devices which use ultrasonic vibration to conduct surgical operations including treatments, such as emulsification, incision, ablation, and coagulation, of anatomy of an object to be treated. In general, the ultrasonic treatment apparatus is provided with a main unit in charge of the drive and control necessary for the ultrasonic treatments, a cable connected to the main unit, and an operation apparatus with a handpiece connected to the cable for the treatments. This handpiece is provided with an ultrasonic transducer generating ultrasonic vibration, a thin and long probe receiving the ultrasonic vibration to transmit the vibration to the distal end thereof, and a casing covering the ultrasonic transducer as well as the outer surface of part of the probe other than the distal treatment device thereof. The ultrasonic transducer is incorporated within a gripping portion of the handpiece griped by an operator.
During use of the ultrasonic treatment apparatus, the vibration caused by the ultrasonic transducer is transmitted to the distal treatment device of the probe through its thin and long body. With the distal treatment device vibrating, the probe is operated to make the distal treatment device come in contact with anatomy to be treated, so that the anatomy is subject to the foregoing ultrasonic treatments.
The conventional handpiece of this kind is proposed by, for example, International publication No. WO 93/05715 (publication 1) and Japanese Patent Laid-open publication No. 2002-253568 (publication 2).
Of these, the publication 1 provides an apparatus that employs the above handpiece, in which there are formed a probe and an ultrasonic transducer through which an aspiration channel is formed. In this handpiece, there is also provided a casing with elongated outer and inner shells formed therein. Between the outer and inner shells, an irrigation channel is formed to supply cleaning fluid. In this apparatus, the cleaning fluid is supplied from the irrigation channel between the outer and inner shells to the tip of the probe, and the cleaning fluid is aspirated through an aspiration hole formed at an axial center part of the probe tip to the aspiration channel formed to axially pass the probe and ultrasonic transducer at the center thereat.
On the other hand, the publication 2 proposes a handpiece, wherein a casing incorporating therein an ultrasonic transducer and providing a gripping portion is placed to have an intermediate layer formed between an innermost layer and an outermost layer within the transducer cover. Both the innermost and outermost layers are formed of electrically insulative material and the intermediate layer is formed of material of which hygroscopicity is different from that of the outermost and innermost layers.
During use of the above ultrasonic treatment apparatus, the ultrasonic transducer located within the gripping portion held by an operator is driven to oscillate continuously. In this operation, the ultrasonic transducer is subjected to the continuous oscillation, resulting in that a fixing portion to fixedly hold a flange of the transducer in the casing of the handpiece will suffer from heat generated from the fixing portion as well as the transducer. This heat generation is an issue to be solved, because, during the use, the heat generated at the fixing portion holding the flange of the transducer in the gripping portion will be transmitted to the surface of the gripping portion, thereby raising the temperature of the gripping portion up considerably high. In addition, when the ultrasonic transducer is driven in a continuous oscillation mode, such vibration will also be transmitted to the gripping portion. The thus-transmitted vibration may reduce a skin friction coefficient of the gripping portion, so that the gripping portion becomes easier to slip from the hands. Thus the vibration on the griping portion may affect operations for the treatments performed under the probe.
Moreover, the configurations proposed by the foregoing publications 1 and 2 have other difficulties.
Within the casing of the handpiece employed by the apparatus proposed by the publication 1, the irrigation channel to supply cleaning fluid is placed between the outer and inner shells. Thus, the irrigation channel may provide a function to prevent the heat and vibration from being transmitted to the gripping portion. However, in this configuration, there should be formed the hole through the axial center part of the probe and ultrasonic transducer. The cleaning fluid also should be fed from the irritation channel between the outer and inner shells to the probe tip, and then the cleaning fluid should be aspirated through the aspiration hole formed at the axial center part of the probe tip to the aspiration channel formed at the center of the probe and ultrasonic transducer. Hence there is a problem that the handpiece itself becomes large in its size, particularly, in the radial direction thereof.
Meanwhile, the apparatus disclosed by the publication 2 should have the casing that not only covers the ultrasonic transducer but also becomes the gripping portion, in which the intermediate layer is formed between the outermost and innermost layers in the cover. However, since the intermediate layer is made of a material whose hygroscopicity is different from that of the outermost and innermost layers, a situation is inevitable where, during the use, the heat caused at the fixing portion fixedly supporting the ultrasonic transducer in the gripping portion finally reaches the outer surface of the gripping portion. Hence the gripping portion of the handpiece cannot be prevented from becoming heated in an effective manner, which is another difficulty that the conventional structure suffers.